Specification of Aluminum Hole Plate
ALUMINUM SPECIFICATIONS
Aluminum is a silver-colored metal which is relatively light and has a density of 2.7 gr cm -3. Properties possessed by aluminum include:
1. Lightweight, corrosion resistant and non-toxic, it is widely used for household appliances such as pots, pans and others.
2. Reflective, in the form of aluminum foil used as a wrapper for food, medicine, and cigarettes.
3. Electrical conductivity is two times greater than Cu, then Al is used as an electric pole cable.
4. Al alloys with other metals produce strong metals such as Duralium (a mixture of Al, Cu, mg) for making board bodies.
5. Al as reducing agent for MnO2 and Cr2O3 oxides.
Aluminum is abundant in the earth's crust, which is around 7.6%. With such abundance, aluminum is the third most abundant element after oxygen and silicon, and is the most abundant metal element. However, Aluminum remains an expensive metal because processing is difficult. An economically valuable aluminum mineral is bauxite which is the only aluminum source. Kriloit is used in aluminum smelting, while clay is widely used to make bricks, ceramics. In Indonesia, bauxite is found on the island of Bintan and in Tayan (West Kalimantan).
Alumininum Processing
Aluminum is made according to the Hall-heroult process discovered by Charles M. Hall in the United States and Paul Heroult in 1886. Processing aluminum and bauxite includes 2 stages:
1. Purification of bauxite to obtain pure alumina.
2. Melting / reducing alumina with electrolysis
Bauxite purification by:
a. Ba is reacted with NaOH (q). Aluminum oxide will dissolve to form NaCl (OH) 4.
b. The solution is filtered and the filtrate containing NaAl (OH) 4 is acidified by flowing CO2 gas Al settles as Al (OH) 3
c. Al (OH) 3 was filtered and then dried and heated so that Al 2 O 3 was not runny. The main Aluminum Ore, among others:
- bauxite
- mica
- clay
Alumina Smelting
This melting uses electrolysis cells which consist of graphite-coated iron containers which also function as cathode (-) while anode (+) is graphite. The mixture of Al2O3 with cryolite and AlF3 is heated to melt and at 950 C then electrolyzed. Al formed in the form of liquid and collected at the bottom of the container and then periodically released into the mold to get aluminum bars (ingots). Graphite anode is continuously spent because it reacts with O2 so it must be replaced from time to time. To get 1 Kg Al is spent 0.44 graphite anode. 2Al2O3 + 3C 4Al + 3CO2
Some of the main ones are:
1. Bauxite (Al2O3. 2H2O)
2. Mika (K-Mg-Al-Slilkat)
3. Clay (Al2Si2O7.2H2O)
Aluminum exists in nature in the form of silicates and oxides, which include:
- as silicates such as feldspar, clay, mica
- as anhydrous oxide eg curondum (for emery)
- as hydrate for example bauxite
- as fluoride eg cryolite.
Use of Aluminum
Some uses of aluminum include:
1. The automotive industry sector, for making truck tubs and motor vehicle components.
2. to make an aircraft body.
3. Housing construction sector, for door and window frames.
4. Food industry sector, for packaging various types of products.
5. Other sectors, for example for electric cables, household furniture and handicrafts.
6. Make a thermite, which is a mixture of aluminum powder with iron (III) oxide powder, used to weld steel in place, for example to connect the railroad tracks.
Some Aluminum compounds are also widely used, including:
1. Alum (K2SO4.Al2 (SO4) 3.24H2O)
Alum has the chemical formula KSO4.AL2. (SO4) 3.24H2O. Alum is used to purify water in drinking water treatment.
2. Alumina (Al2O3)
Alumin is divided into alfaallumina and gamma-allumina. Gamma-alumina is obtained from heating Al (OH) 3 below 4500C. Gamma-alumina is used for aluminum manufacturing, for toothpaste, and for the ceramics industry and glass industry. Alpha-allumina is obtained from heating Al (OH) 3 at temperatures above 10000C. Alpha-allumina is found as corundum in nature which is used for sandpaper or grinda. Precious stones, such as rubies, sapphires, amethysts, and topaz are alpha-allumina containing compounds of transition metal elements that give color to the stone. The colors of rubies include:
- Red rubies because they contain chromium (III) compounds
- Sapphire is blue because it contains iron (II), iron (III) and titan (IV) compounds
- Ametis is violet because it contains chromium (III) and titan (IV) compounds
- Yellow topaz because it contains iron (III)
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